Ivona Djurkin Kušec

The impact of frozen storage duration on physical, chemical and microbiological properties of pork

The aim of the present study was to evaluate the effect of frozen storage duration (3, 6, 9, 12, 15, 18 months) on physical, chemical and microbial properties of pork in three cuts (loin, ham, and belly rib). During frozen storage, significant alterations in physical and chemical parameters were observed through the increase of the total exudate, pH and lightness (L*), and a decrease of shear force and yellowness (b*). Water content in ham samples decreased, while protein content increased. The lipid oxidation (TBA) values in loin and ham samples increased for up to fifteen months of frozen storage, after which they decreased. The proportion of saturated fatty acids in frozen samples was significantly higher than in fresh meat. The total amount of Enterobacteriaceae, S. aureus and Pseudomonas spp. decreased during frozen storage, indicating that freezing may reduce the number of bacteria found in meat. Frozen pork microflora did not change after eighteen months of storage.

Genetic diversity of autochthonous pig breeds analyzed by microsatellite markers and mitochondrial DNA D-loop sequence polymorphism

Abstract The evaluation of the genetic structure of autochthonous pig breeds is very important for conservation of local pig breeds and preservation of diversity. In this study, 18 microsatellite loci were used to detect genetic relationship between autochthonous pig breeds [Black Slavonian (BS), Turopolje pig (TP), and Croatian wild boar] and to determine phylogenetic relationship among Croatian autochthonous pig breeds and certain Asian and European pigs using the mitochondrial DNA (mtDNA) D-loop sequence polymorphism. Relatively high degree of genetic variation was found between the observed populations. The analysis of mtDNA showed that haplotypes of the studied pig populations are different from the other European and Chinese haplotypes. BS pigs showed some similarities with Mangalitsa and Duroc breeds. The genetic distances of TP can be explained by high degree of inbreeding during the past century. Despite the European origin of Croatian pig breeds with some impact of Chinese breeds in the past, the results of present study show that genetic diversity is still pronounced within investigated breeds. Furthermore, the genetic diversity is even more pronounced between Croatian breeds and other European and Chinese pig breeds. Thus, conservation of Croatian pig breeds will contribute to overall genetic diversity preservation of pig breeds.

Efficiency of PCR-RFLP and species specific PCR in identification of meat origin in dry sausages

The purpose of the investigation was the identification of chicken, beef and sheep meat in pork sausages using PCR-RFLP and PCR with species specific primers. Six dry fermented pork sausages were produced by adding beef, sheep and chicken meat to each in the amount of 1% and 5%. DNA was extracted from five locations of each sausage and PCR-RFLP together with PCR using species specific primers was performed. PCR-RFLP analysis was successful only for chicken meat, while species specific PCR was effective for identification of chicken, beef and sheep meat in all ratios and at all locations. The results of our study showed that in investigated products discovering of adulteration using PCR-RFLP is suitable only for chicken meat, while for detection of beef and sheep meat use of species specific oligonucleotides is more adequate.